hmm im sure microsoft will address this soon, but yea if you minimize the window for your xbox one stream to your pc then it ends the stream. So basically if you want to check your emails or browse the net for a second you need to not minimize the window otherwise it will end the stream.
You can resize the window so that it isnt fullscreen which is useful but its what you'd expect anyway. Hopefully soon ill be able to minimize the window without killing the stream.
Cmon Bill, sort it out son :)